A Peninsula ballot measure that would limit the pay of executives at El Camino Hospital faces its toughest opposition from the hospital, which has donated three-quarters of the campaign funds to defeat the proposal. El Camino Hospital has contributed $149,000 in an attempt to defeat Measure M, which would cap the annual salary and compensation package for hospital executives, managers and administrators to twice the salary of the governor of California. At least nine other hospital executives also would see their compensation shrink if local voters approve Measure M on Nov. 6, according to hospital spokeswoman Chris Ernst.